Stiff back roller chain device

ABSTRACT

A sprocket driven stiff back roller chain device for use as a stowable ammunition rammer rod in which a single row of box links, having spaced apart links, are pivotally interconnected by pin-rollers, each of the box links having a cam actuated link latch lever pivotally mounted thereon and adapted to engage a pin on the next adjacent box link to releasably lock these box links together into a stiff rammer rod.

United States Patent Hayes et al. July 3, 1973 [54} STIFF BACK ROLLER CH I VI 980,181 l/l911 Asbury 89/47 [75] Inventors: John R. Hayes; George E. Collins,

both of Indianapolis, Ind. Primary Examiner-Charles J. Myhre Assistant Examiner-A. Russell Burke [73] Assgnem 322:3 mats Corporation A norney-J. L. Carpenter and Arthur N. Krein [22] Filed: Feb. 23, 1972 ST AB ACT 21 'Appl. No.: 228,686 [57] R A sprocket driven stiff back roller chain device for use [52] U 8 Cl 74/245 R 74,250 89/47 as a stowable ammunition rammer rod in which a single [5] 1 l Fug 15/02 9/00 row of box links, having spaced apart links, are pivotl58] Fie'ld 74/256 R 250 S ally interconnected by pin-rollers, each of the box links 74/250 C S 89/47 having a cam actuated link latch lever pivotally mounted thereon and adapted to engage a pin on the I 5 6] References Cited next adjacent box link to releasably lock these box links UNITED STATES PATENTS together into a stiff rammer rod. 987,513 3/1911 Vogeler 89/47 7 Claims, 3 Drawing Figures STIFF BACK ROLLER CHAIN DEVICE The invention herein described was made in the course of work under a contract or subcontract thereunder with the Department of Defense.

This invention relates to roller chains and, in particular, to a stiff back roller chain device.

In an ammunition loader for a large caliber breech loading gun, such as a tank gun, it is necessary to use a rammer rod to push a round of ammunition through a loading tube into the breech of the gun. When such a breech loading gun is mounted on a tank, space limitations require that a stowable rammer rod or column be used in lieu of a rigid rammer rod. Such a stowable rammer, in the form of a pair of roller rammer chains, is disclosed, for example, in copending U.S. application Ser. No. 93,606, entitled Rammer Head" filed Nov. 30, 1970 in the names of John R. Hayes, Francis H. Eckart and Donald E. Peck and is assigned to the same assignee as the subject application and now U.S. Pat. No. 3,670,624. The purpose of the rammer chains in such a structure is to form a nearly -foot pole or rod capable of transmitting up to 750 pounds of ramming force without significant deflection.

Prior to this invention, double roller chains were the best solution found for forming a stowable rammer rod that is capable of folding as necessary to meet the space limitations within a vehicle such as a tank on the return of the rammer rod from the rammer structure. In such a ramming rod device, the maximum load on the roller chains forming the rammer pole occurs at the end of the ramming stroke when the round of ammunition is being seated into the breech of the gun. In such devices, since rods of the chain drive sprockets are used as a feedback signal of rammer position to the control system of the loading apparatus for the gun, any buckling or other shortening of the roller chain rammer rod under load creates a control problem.

It is therefore the primary object of this invention to improve a roller chain device for use as a stowable rammer rod in an ammunition loader whereby a single roller chain can be used to form a stiff back rammer rod which is collapsible so as to limit the space required for stowing the rammer rod.

Another object of this invention is to improve a roller chain device whereby the links of a normally flexible roller chain are adapted to be interlocked with respect to each other to provide a stiff back roller chain ram rod device. I

These and other objects of the invention are attained by means of open-ended, box links, each pivotally interconnected by pin-rollers to adjacent box links on opposite ends thereof. Each box link has a locking bar pivotally mounted intermediate its ends for locking engagement with a pin fixed on the next adjacent box link, the locking bars being provided at opposite ends thereof with cam surfaces engageable by a cam roller adjacent to the path of travel of the roller chain opposite the roller chain drive sprocket to effect locking and unlocking of each locking bar in relation to the pin on the next adjacent box link depending on the direction of travel of the roller chain.

For a better understanding of the invention, as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a plan view of the stiff back roller chain structure of the invention with parts broken away to show the details of the structure;

FIG. 2 is a sectional view taken along line 22 of FIG. 1; and,

FIG. 3 is a perspective view of one of the box links of the roller chain of the invention.

Referring now to the drawings and, in particular, to FIG. 1, there is illustrated a stowable ammunition rammer rod in the form of a stiff back roller chain device in accordance with the invention which includes a roller chain 10 driven and guided by a sprocket l1 and further guided by a storage guide track 12. Sprocket 11 is fixed to a shaft 14 suitably journaled on a base plate 5 for this apparatus and is driven by a suitable drive mechanism, not shown, so that depending on the direction of rotation of the sprocket 11, it will drive and guide the chain 10 past a cam actuator 15 in a first or rammer direction, shown by arrow A in FIG. 1, whereby the locking levers on each of the box links 16 of the roller chain are actuated to interlock these box links with each other to provide a stiff rammer pole or rod, in a manner to be described, and in a second or stowing direction, shown by arrow B in FIG. 1, so that these box links are free to pivot with respect to each other for movement around sprocket and for stowage.

Roller chain 10 consists of a top row of links 20 and a bottom row of links 21, with reference to the position of these links as shown in the drawings, the rows of links being in spaced apart relation to each other and pivotally secured at their ends to their respective adjacent leading and trailing links by pins 22 carrying rollers 23 for driven engagement with the sprocket 11 whereby this chain device can be moved in the directions previously described.

Now in accordance with the invention, and as clearly illustrated in FIGS. 2 and 3, the paired links 20 and 21 of each row of links are rigidly interconnected together in spaced apart relation to each other as by a web 24 to form a rigid box link 16. For ease in manufacturing, each box link is formed as a unitary open-ended box link of substantial U-shape in cross section, the elongated links 20 and 21 forming the side walls or legs thereof and the web 24 forming the base thereof positioned at right angles to the links 20 and 21.

Each of the links 20 and 21 is provided at the free side thereof, that is, the side of each link opposite from web 24, within an outwardly extending apertured pivot boss 25 at one end and at its other end with an outwardly extending apertured pivot boss 26, the latter bosses 26, as clearly seen in FIG. 2, being deformed outward from the normal plane of the links a sufficient distance so that the spacing therebetween on each box link is such as to slidably receive the pair of bosses 25 of the next adjacent box link therebetween. Thus, as shown in FIGS. 2 and 3, the bosses 25 of one box link are slidably and pivotally received between the bosses 26 of the next adjacent box link, each of these box links being pivotally interconnected by means of a pivot pin 22 extending through the apertures in these bosses and through a roller 23 journaled on the pin 22 and positioned between the bosses 25.

In addition, each box link is constructed so that the bosses 25 and 26 extend longitudinally outward from the main body portion of the box links whereby when they are pivotally interconnected, each box link is free to pivot in one direction relative to the adjacent box link to permit movement of these box links around a curve, as defined, for example, by the sprocket 11, but when moved in a straight line the straight end faces 27 of the links 20 and 21 and of the web 24 of one box link will abut against the corresponding faces of the next adjacent box link to prevent pivotal movement of one box link relative to its adjacent box link in the opposite direction, that is, in a counterclockwise direction with reference to the topmost box link shown in FIG. I.

In addition, the leading end of the leading box link, with respect to the direction of travel indicated by arrow A in FIG. 1, is connected in a suitable manner to a rammer head, not shown, since it forms no part of the subject invention, which may be of the type disclosed in the above referenced United States application Ser. No. 93,606.

To effect interlocking engagement of adjacent box links to form a stiff back chain for use as a rigid rammer rod, each box link is provided with a link latch lever 30 having a pin engaging notch 31 of one side thereof, the link latch lever being pivotally mounted intermediate its ends on one side of the box link for movement into and out of locking engagement with a lock pin 32 on the adjoining trailing box link, with reference to the direction of travel as shown by arrow A of FIG. 1.

As shown more clearly in FIG. 2, a link latch lever 30 is pivotally mounted on the upper surface of the link 20 portion of a box link by a pivot pin 33 which is provided with a head portion 33a to axially retain the link latch lever in position. As shown, the pivot pin 33 extends through suitable apertures in the lever 30 and in the links 20 and 21, the pivot pin being staked at its opposite end from head 33a to the link 21.

Each link latch lever 30 is provided at opposite ends thereof with cam edge portions 34 and 35, one or the other of these latch portions normally extending outward beyond the plane of the web 24 of the box link for engagement with the cam actuator to effect locking or unlocking of the lever relative to a lock pin 32 on the next adjacent box link depending on the direction of movement of the box links 16 of the roller chain past the cam actuator. On the same side of the link latch lever as the notch and opposite the cam edge portion 34, the latch is provided with a guide edge portion 36 of suitable length so that either the notch 31 of this guide portion 36 of the link latch lever will engage the lock pin 32 on the adjoining box link to limit pivotal movement of the link latch lever in one direction, that is, in a counterclockwise direction as seen in FIG. 1, an edge portion 37 being provided at the end opposite edge portion 36 to limit movement of the link latch lever in the opposite direction.

To guide the roller chain into and out of driven tangential engagement with the sprocket 11 and to guide and retain the respective box links thereof for actuation of the link latch levers thereon, there is provided a guide track 12 suitably fixed relative to the sprocket 11 and to cam actuator 15, as by being secured to the base plate 5, the guide being formed to provide straight run guide portions 12a and 120 leading into and away from the sprocket, in terms of the direction of arrow A, and an intermediate guide portion 12b formed in an are complementary to a section of the sprocket 11 as seen in FIG. 1. As shown in FIGS. 1 and 2, the guide track is substantially U-shape in cross section at the guide portion 12c with upright leg portions 40 and 41 connected together by a slotted web 42.

As shown in FIGS. l and 2, an upright retaining rail 43 is suitably secured, as by welding, to the inside of the leg 41 at guide portion 120 terminating adjacent to the cam actuator 15 and extends back through guide portions 12b and 12a. This retaining rail 43 being of sufficient heighth so as to be in interference relationship with the link latch levers 30 to limit their rotation in a clockwise direction with reference to FIG. l as the box links travel in a path around a portion of sprocket It.

In addition, as shown in FIG. 2, a guide rail 44 is secured inside the upright guide rail 43 on leg 41 in the straight run guide portion 120 adjacent to the cam actuator 15 in position to be engaged by a guide wheel or roller 50 on each box link rotatably journaled on a shaft 51 fixed to links 20 and 21, the guide wheel or roller 50 being positioned between the links 20 and 21 with an aperture 28 being provided in the web 24 of each box link whereby a portion of this guide wheel or roller can extend beyond the box link for engagement with the guide. On the opposite side of the guide track from guide rail 44 there is provided, again adjacent to the cam actuator 15, a second guide rail 45 fixed to the upright 40, as seen in FIG. 2, in position to be engaged by the rollers 23 on the box links 16. These guide rails 44 and 45 in cooperation with the rollers 50 and 23 on each box link act to limit side to side movement of the box'links as they move adjacent to the cam actuator 15, as seen in FIG. 2. The leg of the guide track 12 as it extends around the sprocket 11 is provided with a slot 40a to permit one of the legs 11a of the bifurcated peripheral edge of sprocket 11 to extend into the guide track for engagement with the rollers 23 to effect movement of the roller chain, the guide rail being of a heighth less than the distance between these legs of the sprocket.

A second guide rail 44a, of U-shaped cross section, is fixed inside of the upright guide rail 43 in position to receive between the arms thereof the guide wheels of the box links 16.

As shown in FIG. 1, the cam actuator 15 is suitably positioned on the base plate 5 at a location adjacent to the path of travel of the roller chain in a straight line path as defined by guide portion 12c and closely adjacent to the sprocket 11. Although any suitable form of cam actuator 15 may be used to effect actuation of the link latch levers on the respective box links, in the embodiment shown the cam actuator is in the form of a truncated cam actuator roller suitably journaled on a shaft 61' supported on the base plate 5. As shown more clearly in FIG. 2, the cam actuator roller 60 is provided with an annular flange portion 62 of a radius to overlap the link latch levers so as to limit upward travel thereof, with reference to FIG. 2, of a box link as its link latch lever is actuated. The cam actuator roller 60 is also provided with a lower tapered peripheral portion 63 terminating in a cylindrical peripheral portion 64 adjacent to the flange portion 62 for engagement with the cam portions 34 and 35 of a link latch lever 30.

At least in the guide portion 12c, the box links 16 are also supported against downward vertical deflection, with reference to FIG. 2, by means of guide rollers 66, each supported on a stub shaft 67 fixed to the web 42 of the guide track, each of the guide rollers being positioned within suitable slots 42a provided for this purpose in the web 42 of the track guide. With this arrangement, the box links 16 are supported so that as a link latch lever 31) is actuated to effect interlocking of the respective box links together, the notch 31 of the lever will engage the lock pin 32 on the next adjacent link beneath the head 32a of the lock pin. As seen in FIG. 3, a lock pin 32 is suitably fixed, adjacent one end of the box link, opposite the link latch lever thereon, to the link 20 with the head 32a of the lock pin spaced from the surface of the link 20 so as to slidably receive the link latch lever 30 of the next adjacent box link, whereby the notch 31 thereon can engage the body of the lock pin.

In operation, with the sprocket 11 rotating in a clockwise direction as seen in FIG. 1, each of the adjoining box links 16 advancing to and around this sprocket is free to pivot with respect to its next. adjacent box link about the axes of the pins 22 joining these box links together. On each of the box links 16 advancing to and around the sprocket 11, the link latch lever 30 thereon is in a relative rotated position so that its notch 31 is out of engagement with the pin 32 on the next trailing box link, in terms of the direction of travel of these box links with the sprocket ll rotating clockwise, and so that its cam portion 34 extends outward over the edge of the link 20 to which the lever is pivotally secured.

As each box link is moved toward and around sprocket 11 rotating clockwise, the box link is guided first in a path toward the sprocket by the guide portion 12a of the guide track 12, then around the sprocket by the guide portion 12b and then away from the sprocket in a straight line path by the guide portion 12c. When a box link enters guide portion 120, it is immediately aligned with the next adjacent leading box link traveling in a straight path, in the direction of arrow A in FIG. 1, with its leading end face 27 moved into substantially abutting relation against the trailing end face 27 of the next adjacent leading box link. Then, as the leading box link advances in a path of travel adjacent to the cam actuator 15, the cam edge portion 34 of the link latch lever 30 on this box link will engage the cam actuator whereby this link latch lever is caused to rotate in a counterclockwise direction, as seen in FIG. 1,

whereby its notch 31 will become engaged with the lock pin 32 on the next adjacent trailing box link to effectively lock these two box links together. At the same time as this occurs, the cam edge portion 35 of this link latch lever 30 is moved into a position to extend beyond the edge of the link to which this link latch lever is pivotally secured, in the position of these levers as shown on the uppermost box links in FIG. 1. As adjacent box links are thus interconnected in the manner just described, they form a stiff back roller chain structure suitable for use as a rigid rammer rod for the purpose previously described.

When the sprocket 11 is rotated in a counterclockwise direction, as seen in FIG. I, the thus previously interconnected box links are again moved in a path of travel adjacent to the cam actuator 15 so that as each successive box link travels past the cam actuator, the cam edge portion 35 of the link latch lever on a box link engages the cam actuator 15 causing the link latch lever to pivot in a clockwise direction, as seen in FIG. 1, about the axis of pivot pin 33 so as to disengage the lever from the lock pin 32 of the next adjacent b'ox link whereby these two box links are again free to pivot with respect to each other about the axis of their connecting pin 22. As this occurs, each successive box link is then free to travel around the sprocket 11 for stowage as desired.

What is claimed is:

1. A stiff back roller chain structure comprising a roller chain having a first row and a second row of a plurality of links hinged to each other by pin means adjacent one side thereof with said first row of links in spaced relation with respect to said second row of links, web means secured to paired links of said first row and said second row of links to rigidly maintain said paired links in said spaced apart relation, each of said links in said first row having a lock pin fixed thereon adjacent one end and on the opposite side of said pins and a pivotally mounted link latch lever at its opposite end, said link latch lever having notch means thereon for locking engagement with the said lock pin on the next adjacent link and having cam means on opposite ends thereof positioned so that depending on the relative rotative position of said latch link lever on its link, one of said cam means extends beyond said link, a roller chain drive sprocket rotatively mounted to engage said pin means whereby to effect movement of said roller chain, guide track means positioned adjacent to said drive sprocket to guide said roller chain into and out of driven engagement with said drive sprocket and, a cam actuator mounted adjacent to said guide track means on the opposite side of said guide track means from said drive sprocket in position to engage said cam means to effect pivotal movement of said link latch lever.

2. A stiff back roller chain structure according to claim 1 wherein each of said links of said roller chain is provided with a first apertured boss near one end for receiving one of said pin means and a second apertured boss at its opposite end for receiving one of said pin means, said first apertured bosses on one set of paired links being spaced apart to slidably receive said second apertured bosses on the next adjacent set of paired links.

3. A stiff back roller chain structure according to claim 1 wherein said roller chain further includes a guide wheel means rotatably mounted between each set of paired links of said first row and said second row of said links in position to engage said guide track on the opposite side of said pin means.

4. A stiff back roller chain structure including a roller chain having a plurality of box links of substantially U- shape in cross section, each of said box links including two elongated links arranged facing and parallel to each other and an integral web portion, pin means pivotally connecting together adjacent box links on one side thereof opposite said web portion, a lock pin fixed on one side of each of said box links and a link latch lever pivotally mounted on said same side and at the opposite end of each of said box links from said lock pin thereon, each of said link latch levers having notch means thereon for locking engagement with said lock pin on said next adjacent box link, each of said link said drive sprocket in part to guide said roller chain into and out of driven engagement with said drive sprocket and, a cam actuator mounted adjacent to said guide track means on the opposite side of said drive sprocket in position to engage said cam means on said link latch lever as said box links are moved adjacent said cam actuator whereby said box links are intercon nected together by actuation of said link latch levers to engage said lock pins when said box links are moved in one direction and to effect unlocking of said link latch means relative to said lock pins when said box links are moved in the opposite direction.

5. A stiff back roller chain structure according to claim 4 wherein said web portion of each of said box links is provided with a longitudinally extending aperture and wherein each of said box links further includes a guide wheel means pivotally mounted between said links in position to extend through said aperture to engage said guide track and wherein said pin means includes a pivot pin and a roller rotatably mounted on each of said pins in position between the links of a box link for engagement by said drive sprocket.

6. A stiff back sprocket driven roller chain comprising a plurality of box links, each of said box links including elongated links arranged facing and parallel to each other and a web portion integral with said links toward one side thereof and at right angles thereto, each of said links having a first apertured boss near one end thereof and a second apertured boss at its opposite end, said first and said second apertured bosses being on the opposite side of said links from said web, said first apertured bosses on the links on one of said box links being spaced apart to slidably receive said second apertured bosses on the links of the next adjacent box link, said box links being pivotally connected together by a pivot pin mounted in said first apertured bosses and said second apertured bosses of adjoining box links, a sprocket engaging roller rotatably mounted on each of said pins and positioned between said second apertured bosses on a box link, a lock pin fixed on one side and end of each of said box links and a link latch lever pivotally mounted on said same side and at the opposite end of each of said box links, each of said link latch levers having notch means thereon for locking engagement with the lock pin on the next adjacent box link and having cam means on opposite ends thereof with at least one of said cam means always positioned to extend beyond the box link on which the said link latch lever is mounted for engagement by a cam actuator.

7. A stiff back sprocket driven roller chain according to claim 6 wherein each of said box links further includes a guide wheel means rotatably mounted between the said links of each box link in position to extend beyond one side of said links opposite said bosses. 

1. A stiff back roller chain structure comprising a roller chain having a first row and a second row of a plurality of links hinged to each other by pin means adjacent one side thereof with said first row of links in spaced relation with respect to said second row of links, web means secured to paired links of said first row and said second row of links to rigidly maintain said paired links in said spaced apart relation, each of said links in said first row having a lock pin fixed thereon adjacent one end and on the opposite side of said pins and a pivotally mounted link latch lever at its opposite end, said link latch lever having notch means thereon for locking engagement with the said lock pin on the next adjacent link and having cam means on opposite ends thereof positioned so that depending on the relative rotative position of said latch link lever on its link, one of said cam means extends beyond said link, a roller chain drive sprocket rotatively mounted to engage said pin means whereby to effect movement of said roller chain, guide track means positioned adjacent to said drive sprocket to guide said roller chain into and out of driven engagement with said drive sprocket and, a cam actuator Mounted adjacent to said guide track means on the opposite side of said guide track means from said drive sprocket in position to engage said cam means to effect pivotal movement of said link latch lever.
 2. A stiff back roller chain structure according to claim 1 wherein each of said links of said roller chain is provided with a first apertured boss near one end for receiving one of said pin means and a second apertured boss at its opposite end for receiving one of said pin means, said first apertured bosses on one set of paired links being spaced apart to slidably receive said second apertured bosses on the next adjacent set of paired links.
 3. A stiff back roller chain structure according to claim 1 wherein said roller chain further includes a guide wheel means rotatably mounted between each set of paired links of said first row and said second row of said links in position to engage said guide track on the opposite side of said pin means.
 4. A stiff back roller chain structure including a roller chain having a plurality of box links of substantially U-shape in cross section, each of said box links including two elongated links arranged facing and parallel to each other and an integral web portion, pin means pivotally connecting together adjacent box links on one side thereof opposite said web portion, a lock pin fixed on one side of each of said box links and a link latch lever pivotally mounted on said same side and at the opposite end of each of said box links from said lock pin thereon, each of said link latch levers having notch means thereon for locking engagement with said lock pin on said next adjacent box link, each of said link latch levers further including cam means on opposite ends thereof on the opposite side of said notch means, said cam means being provided on said link latch lever means so that at least one of said cam means is always positioned beyond the box link on which the said link latch lever is mounted, a roller chain drive sprocket relatively mounted to engage said pin means to effect movement of said roller chain, a guide track means positioned adjacent to said drive sprocket and encircling said drive sprocket in part to guide said roller chain into and out of driven engagement with said drive sprocket and, a cam actuator mounted adjacent to said guide track means on the opposite side of said drive sprocket in position to engage said cam means on said link latch lever as said box links are moved adjacent said cam actuator whereby said box links are interconnected together by actuation of said link latch levers to engage said lock pins when said box links are moved in one direction and to effect unlocking of said link latch means relative to said lock pins when said box links are moved in the opposite direction.
 5. A stiff back roller chain structure according to claim 4 wherein said web portion of each of said box links is provided with a longitudinally extending aperture and wherein each of said box links further includes a guide wheel means pivotally mounted between said links in position to extend through said aperture to engage said guide track and wherein said pin means includes a pivot pin and a roller rotatably mounted on each of said pins in position between the links of a box link for engagement by said drive sprocket.
 6. A stiff back sprocket driven roller chain comprising a plurality of box links, each of said box links including elongated links arranged facing and parallel to each other and a web portion integral with said links toward one side thereof and at right angles thereto, each of said links having a first apertured boss near one end thereof and a second apertured boss at its opposite end, said first and said second apertured bosses being on the opposite side of said links from said web, said first apertured bosses on the links on one of said box links being spaced apart to slidably receive said second apertured bosses on the links of the next adjacent box link, said box links being pivotally connected togethEr by a pivot pin mounted in said first apertured bosses and said second apertured bosses of adjoining box links, a sprocket engaging roller rotatably mounted on each of said pins and positioned between said second apertured bosses on a box link, a lock pin fixed on one side and end of each of said box links and a link latch lever pivotally mounted on said same side and at the opposite end of each of said box links, each of said link latch levers having notch means thereon for locking engagement with the lock pin on the next adjacent box link and having cam means on opposite ends thereof with at least one of said cam means always positioned to extend beyond the box link on which the said link latch lever is mounted for engagement by a cam actuator.
 7. A stiff back sprocket driven roller chain according to claim 6 wherein each of said box links further includes a guide wheel means rotatably mounted between the said links of each box link in position to extend beyond one side of said links opposite said bosses. 